A navigation system performs travel guidance for enabling a user to easily and quickly reach the selected destination. A typical example is a vehicle navigation system where a vehicle is equipped with a navigation function to guide a driver to a destination through a calculated route. Such a navigation system detects the current position, and reads out map data pertaining to an area at the current position from a data storage medium such as a DVD. Typically, the navigation system displays a map image on a monitor screen while superimposing thereon a mark representing the current location of the user. At an intersection, the navigation system notifies the user which direction to turn at the intersection.
FIGS. 1A-1H show examples of overall procedure and screen display involved in the navigation system for a travel to a destination. FIG. 1A shows an example of locator map screen of the navigation system when the destination is not specified. Typically, the navigation system displays a street on which the vehicle (vehicle position VP) is running on a map image and a name of the street. Other information such as a north pointer NP, a map scale and a current time may also be illustrated on the display screen.
An example of process for specifying a destination in the navigation system through a Point of Interest (POI) search method is shown in FIGS. 1B-1F. A main menu screen shown in FIG. 1B displays menu items including a “Destination” menu for selecting the destination. When selecting “Destination”, the navigation system displays a “Find Destination by” screen shown in FIG. 1C for specifying an input method for selecting the destination. The “Find Destination By” screen lists methods for selecting the destination including “Address”, “Intersection”, and “Point of Interest (POI)”.
When selecting, the “Point of Interest” method in FIG. 1C, the navigation system displays selection methods of POI either by “Place Name” or “Place Type” in FIG. 1D. The “Place Name” is to specify a name of POI, and the “Place Type” is to specify a category of POI. If the “Place Type” is selected in FIG. 1D, the navigation system lists categories of POIs as shown in FIG. 1E. The user selects a desired category of POIs from the lists.
FIG. 1F shows a screen when the user has selected a “Fast Foods” category in the example of FIG. 1E. In this example, the screen includes the name of POI type “Fast Foods” at the top and a list of names of the fast food restaurants typically sorted by distance from the current position. Because “Burger King” is the nearest location, it is listed on the top. The user selects a particular restaurant among the lists for route guidance.
In FIG. 1G, the navigation system displays a progress scale during the calculation of the route to the destination. After determining the route, the navigation system starts the route guidance as shown in FIG. 1H. Typically, the navigation system shows the intersection that is highlighted to show the next turn and a direction of the turn. The search method in the conventional navigation system works in the foregoing manner.
There arise a situation where a user who wants to search multiple POIs of the same type and name and obtain the most efficient route to accomplish the particular purpose. In the conventional navigation system, when POIs are displayed on the map image of the navigation system, generic icons are displayed. For example, generic icons representing restaurant or gas station may be superposed on the map as shown in FIG. 2. A generic icon will not differentiate individual stores but simply indicates the type of the POIs. Thus, fast food restaurants such as “McDonald”, “Burger King”, “Pizza Hut”, etc., are represented by the same generic icon of restaurant.
Thus, in the example of FIG. 2, since all the nearby restaurants are indicated by the generic icons for restaurant, the user cannot easily distinguish which icons indicate what kind of restaurant. If the user wants to go to a particular restaurant, for example, “Pizza Hut”, the user cannot tell whether “Pizza Hut” exists just by looking at the map image of FIG. 2. Moreover, the user may wish to fill gasoline at a particular gas station chain store such as “Chevron”, “Arco”, etc., for instance, because the user can use a reward card, or at a gas station chain store the user knows to offer competitive prices.
Accordingly, there is a need of a more efficient way of identifying particular types and names of POI to improve the operability of the navigation system.